stohlen



March 3, 1964 F. STUHLEN 3,122,960

BOW FOR A STRING INSTRUMENT Filed Aug. 4, 1961 Fig.1

70 iii 7 17 INVENTOP :FERDM/M/D STGHLEM GENT United States Patent 3,122,960 BOW FOR A STRING INSTRUMENT Ferdinand Stiihlen, Bonn, Germany, assignor to Dr. Plate G.m.b.H., Bonn (Rhine), Germany Filed Aug. 4, 1961, Ser. No. 129,323 Claims priority, application Germany Aug. 17, 1960 13 Claims. (Cl. 84-282) The present invention relates to improvements in bows for string instruments, and more particularly to improved synthetic resin filaments for such bows and methods for their manufacture.

Attempts to use polyamide filaments of circular cross section for bows of musical string instruments have heretofore not been successful because bows with such filaments do not impart the required oscillations to the strings. The same difficulty has been encountered with generally circular vinylidene chloride bow filaments. It has been proposed to overcome this difiiculty by roughening the surface of such synthetic resin bow filaments or by twisting several mono-filaments into a cord or by placing a lace web about it. Attempts have also been made to eliminate the disturbing elasticity of synthetic resin bow filaments. However, all the conventional measures to adapt synthetic resins for the use of bow filaments have been unsuccessful.

It is the primary object of the present invention to overcome the various disadvantages heretofore encountered and to make it possible to use synthetic resins as a material for making filaments for bows of musical string instruments, which will bring out the full tonal quality of the strings.

This and other objects and advantages are accomplished in accordance with this invention by using elongated synthetic resin filaments for bows, each filament having a non-circular transverse cross section and a permanent twist about its longitudinal axis and along its entire length. Synthetic resin bow filaments of such a structure impart the necessary oscillations to the strings of a musical instrument. A plurality of such synthetic resin filaments may be stretched between the two rod ends of a bow in the conventional manner.

Useful synthetic resins are thermoplastic, fiber-forming polymers which are hydrophobic.

The above and other objects and features of the invention will be more fully understood by reference to the following detailed description of certain preferred embodiments thereof, taken in conjunction with the ac companying drawing wherein:

FIG. 1 is a side view of a bow for a musical string instrument;

FIGS. 2 to 6 show various non-circular transverse cross sections of bow hair according to the invention; and

FIG. 7 is a perspective view of a part of a bow hair illustrating its permanent twist.

Referring now to the drawing and first to FIG. 1, there is shown a conventional bow 1 consisting of a rod, for instance of wood, with one end or head portion 10 and another end which carries a tension lock 11. A plurality of filaments 12 are stretched between the end portions of the rod, being fixedly attached to head portion 10 and held under tension by tension lock 11, as is well known. For purposes of illustration, one of the filaments 12 is shown detached from the tension lock.

FIGS. 2 to 6 show different transverse cross sections of the filament, FIG. 2 illustrating the preferred elliptical cross section, while FIG. 3 shows a rectangular cross section, FIG. 4 a trapezoidal cross section and FIG. a polygonal cross section with a narrowed median section 15. In the embodiment of FIG. 6, a plurality of longitudinally extending grooves 17 are formed in the surface of the filament.

3,122,960 Patented Mar. 3, 1964 Preferably, the ratio of the longest axis of the cross section of the filament (indicated at 13 in FIG. 2) to the shortest axis perpendicular thereto (indicated at 14 in FIG. 2) is between 111.2 and 1:3.

It is obvious that, while certain specific cross sections have been illustrated, any polygonal cross section could be chosen instead of the preferred elliptical cross section.

FIG. 7 shows a section of the filament with a permanent twist along its longitudinal axis 16. Preferably, about 12 to 18 turns per meter of filament are used, a turn being defined as a twist of the hair about its longitudinal axis by 360".

The synthetic resin for the bow filaments of this invention may be any suitable, hydrophobic thermoplastic resin which absorbs or adsorbs no more than about 4% of water when saturated. The polyamides have been found useful, particularly 610 polyamide (a polymer of hexamethylenediamine and sebacic acid), 8 polyamide (from w-aminocaprylic acid) and 11 polyamide (from w-aminoundecanoic acid). Polyestens, such as polyethylene terephthalate, may also be used. Other useful plastics include polyurethane, such as one composed of hexamethylenediisocyanate and butyleneglycol, and polyethylene.

Polyethylene adsorbs or absorbs practically no water; polyethylene terephthalate and polyurethane less than 1%; ll polyamide about 1%; 610 polyamide about 3% and 8 polyamide about 4%.

If desired, a pigment may be added to the synthetic resin melt before the filaments are extruded whereby any desired permanent and abrasion-resistant coloration may be imparted to the bow hairs. For instance, a yellowish tint may be imparted to the filaments to imitate the color of natural horsehairs. It is desirable, of course, to use pigment-s which are not decomposed during melt spinning and which are inert to the resin, for instance, titanium dioxide, cadmium sulfide, cadmium selenide, carbon black and the like. It would also be possible to dye the synthetic resin filaments after spinning but such coloration obviously will not be as abrasion-resistant as that obtained by incorporating a pigment in the resin melt before spinning.

The filaments of this invention are produced by extruding the synthetic resin through suitably shaped orifices to impart to the filaments the desired non-circular transverse cross section illustrated, by way of example, in FIGS. 2-6. The filaments are stretched, preferably to four to five times their original length, and twisted, for instance 12 to 18 turns per meter. The stretched and twisted filaments are subjected to a heat treatment to set the twist permanently therein. The preferred heat treatment is immersion in a hot water bath of about 95 C.

The following examples illustrate the practice of this invention.

Example I 610 polyamide filaments were produced in a melt spinning process by extruding the molten resin through a spinneret with elliptically shaped orifices whose axes were 2.5 mm. and 1.2 mm, respectively. The extruded filaments were quenched in water and continuously stretched between godets at a ratio of 1:4.6. The stretched filaments had an elliptical cross section whose axes were 0.20 and 0.13 mm., respectively. Each monofilarnent was twisted 15 full turns per meter. The twisted monofilament was wound on a take-up roller in a layer of about 20 mm. and immersed for an hour in hot water of a temperature of 95 C. to set the twist permanently.

After cooling the twisted monofilament was cut into lengths of cm. and about 250 such filaments were put together, their ends were melted together over a flame and they were then placed into the rod of a violin bow.

After being coated with colophony, the bow produced excellent vibration of the violin strings. Changes in climate or humidity produced no change in the tension of the bow hairs.

Example 11 Polyethylene terephthalate containing 0.2% pigmentation consisting .of titanium dioxide, cadmium sulfide and cadmium selenide was melt-spun in the same manner in Example I, the spinneret orifices being rectangular, with a length of 3 mm. and a width of 1.5 mm. Opposite sides of the rectangular orifices were provided with three recesses of 0.5 mm. width and 0.3 mm. width, respectively. The molten plastic was extruded into a water bath spaced about 5 to 6 cm. from the spinneret face to harden the extruded filaments. The filaments were then stretched to about 4.5 times their original length and the stretched filaments were of rectangular cross section of a length of 0.22 mm. and a width of 0.15 mm., with three longitudinally extending grooves on each side of the filaments. Each monofilament was then twisted about 12 full turns per meter and set by treatment with steam at a temperature of 125 C.

380 of such filaments, cut to a length of 75 cm., were combined and placed into a rod of a bow for a counterbass.

Example III A polymer was prepared in an autoclave by mixing amino-caprylic acid with 4%, by weight, of 11-aminoundecanoic acid and 8%, by Weight, of water and heatingfor five hours in the absence of oxygen from the air to a temperature of 260 C. The resultant pressure of 12 atmospheres was reduced to normal atmospheric pressure andthe autoclave was evacuated for 45 minutes to mm. mercury. Oxygen-free N was then added under a pressure of two atmospheres and the polymer was extruded through orifices of trapezoidal cross-section, the parallel sides of the trapeze having a length of 2.5 and 3.5 mm. and the two other sides having a length of 1.35 mm. The extruded filaments were hardened in a water bath containing 3%, by weight, of an acid dyestufi and 1%, by weight, of acetic acid, and removed from the water bath over chrome-plated godets rotating at a speed of 80 m. per minute. The filaments were then led over chrome plated godets rotating at a speed of 365 m. per minute to stretch the same. The resultant filaments are of trapezoidal to semi-circular cross section and have a weight of 30 mg./m. The stretched monofilaments were twisted 18 full turns per meter and the twist was set by leading the filaments through an infra-red radiation zone.

While the invention has been described and illustrated in connection with certain specific embodiments thereof, it will be clearly understood that many modifications and variations may occur to the skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A bow for a string instrument, comprising a rod having two ends and stretched between the rod ends a plurality of elongated filaments, each filament being composed of a synthetic resin, having an elliptical transverse cross section and a stretch of about 4 to 5 times its original length, the synthetic resin being a fiber-forming, thermoplastic and hydrophobic polymer containing no more than about 4% of water when 'saturated,the ratio of the longest axis of the cross section to the shortest axis perpendicular thereto being between 1:12 and 153, and the filament having a permanent twist along its entire length, the twist consisting of 12 to 18 turns per meter.

2. A bow for a string instrument, comprising a rod having two ends and stretched between the rod ends a plurality of elongated filaments, each filament being composed of a synthetic resin, having a non-circular transverse cross section, a stretch of about 4 to 5 times its original length and a permanent twist along its entire length, the twist consisting of 12 to 18 turns per meter, and the synthetic resin being a fiber-forming, thermoplastic and hydrophobic polymer containing no more than about 4% of water when saturated.

3. The bow .of claim 2, wherein said cross-section is elliptical.

4. The bow of claim 2, a polyamid resin.

5. The bow of claim 4, 610 polyamid resin.

6. The bow of claim 4, 8 polyamid resin.

7. The bow of claim 4, 11 polyamide resin.

8. The bow of claim 4, polyethylene terephthalate.

9. The bow of claim 4, a polyurethane.

10. The bow of claim 2, wherein the fiber-forming, thermoplastic and hydrophobic polymer contains a pigment.

11. The bow of claim 10, wherein said pigment is titanium dioxide.

12. The bow of claim 10, wherein said pigment is selected from the group consisting of cadmium sulfide and cadmium selenide.

13. The bow of claim 10, wherein said pigment is carbon black.

wherein said synthetic resin is wherein said synthetic resin is wherein said synthetic resin is wherein said synthetic resin is wherein said synthetic resin is wherein said synthetic resin is References Cited in the file of this patent UNITED STATES PATENTS 1,773,969 Dreyfus Aug. 26, 1930 1,835,407 Kratochwill Dec. 8, 1931 1,921,426 Niogret Aug. 8, 1933 2,002,153 Mendel May 21, 1935 2,317,485 Rider Apr. 27, 1943 2,637,893 Shaw May 12, 1953 2,891,270 Reiter June 23, 1959 FOREIGN PATENTS 512,677 Germany Nov. 13, 1930 1,004,464 Germany Mar. 14, 1957 

1. A BOW FOR A STRING INSTRUMENT, COMPRISING A ROD HAVING TWO ENDS AND STRETCHED BETWEEN THE ROD ENDS A PLURALITY OF ELONGATED FILAMENTS, EACH ELEMENT BEING COMPOSED OF A SYNTHETIC RESIN, HAVING AN ELLIPTICAL TRANSVERSE CROSS SECTION AND A STRETCH OF ABOUT 4 TO 5 TIMES ITS ORIGINAL LENGTH, THE SYNTHETIC RESIN BEING A FIBER-FORMING, THERMOPLASTIC AND HYDROPHOBIC POLYMER CONTAINING NO MORE THAN ABOUT 4% OF WATER WHEN SATURATED, THE RATIO OF THE LONGEST AXIS OF THE CROSS SECTION TO THE SHORTEST AXIS PERPENDICULAR THERETO BEING BETWEEN 1:1.2 AND 1:3, AND THE FILAMENT HAVING A PERMANENT TWIST ALONG ITS ENTIRE LENGTH, THE TWIST CONSISTING OF 12 TO 18 TURNS PER METER. 